Behaviour change after Spinosad (Comfortis) in dogs

1,176 reports to the FDA describe behaviour change in dogs given Spinosad. That is 2.1% of all reports for this medicine, compared with 2.5% across reports for all dog medicines.

1,176Reports

30%Marked serious

49%Recovered

8.6%Died or euthanised

1 daysTypical onset

How soon it started

Same day

359 47%

1–2 days

79 10%

3–7 days

36 4.7%

1–4 weeks

68 8.9%

Over a month

219 29%

How the animals did

Recovered

405 34%

Recovered with lasting effects

176 15%

Still unwell when reported

110 9.4%

Died

69 5.9%

Euthanised

32 2.7%

Not known

384 33%

Problems reported at the same time

429 36%

354 30%

257 22%

222 19%

136 12%

128 11%

128 11%

Restlessness or agitation

122 10%

Age of the animals

Under 1 year

1–3 years

384

4–7 years

336

8–11 years

224

12+ years

About this medicine

Spinosad kills fleas; monthly chewable.

Products with this ingredient include Comfortis. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.

Questions owners ask

Can Spinosad cause behaviour change in dogs?: 1,176 reports link the two, but a report alone does not prove the medicine was the cause: other illnesses, other medicines or coincidence can be involved. Your vet can judge it for your animal.
How soon after a dose was it reported?: In half of the reports with dates, it started within 1 day of the first dose.
What should I do?: Don't give another dose until you've spoken to your vet, and keep the packaging so you can tell them the product and dose. Your vet can also report it to the FDA (or you can, through the manufacturer or FDA form 1932a).

Behaviour change with similar medicines

Behaviour change after Lufenuron + Milbemycin Oxime (Sentinel) 358 reports · 1.4% of its reports
Behaviour change after Imidacloprid + Moxidectin (Advantage Multi) 1,205 reports · 9.2% of its reports
Behaviour change after Nitenpyram (Capstar) 323 reports · 3.0% of its reports
Behaviour change after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 128 reports · 1.3% of its reports
Behaviour change after Fipronil + S-methoprene (Frontline Plus) 181 reports · 6.1% of its reports
Behaviour change after Flumethrin + Imidacloprid (Seresto) 167 reports · 7.3% of its reports
Behaviour change after Imidacloprid 94 reports · 4.9% of its reports
Behaviour change after Fipronil 66 reports · 4.7% of its reports
Behaviour change after Lufenuron 20 reports · 2.0% of its reports
Behaviour change after Imidacloprid + Permethrin + Pyriproxyfen 70 reports · 9.5% of its reports

All reported side effects of Spinosad in dogs · Medicines most reported with behaviour change